Revert commit 2a602dfb4079a3d2f2e406c5145d0282b498e6e4 and fix the issue by checking presence of network_ipam_refs in obj_dict

Change-Id: If63b6fb479b7ddbdac6d8e7cf715897dc1fb7923
Merge "Revert commit 2a602dfb4079a3d2f2e406c5145d0282b498e6e4 and fix the issue by checking presence of network_ipam_refs in obj_dict"